On a computer system, hardware components (referred to merely as components, below) such as a central processing unit (CPU), a memory, a hard disk drive (HDD), and a power supply unit (PSU) are mounted. When power is supplied and components operate, electric energy is converted into thermal energy and temperatures of the components rise. However, excessive temperature rise causes breakdown or the like of the components. Therefore, a cooling fan is installed in the computer system so as to cool down the components by air blown from the fan.
A related technique is disclosed in Japanese Laid-open Patent Publication No. 2010-211269 or Japanese Laid-open Patent Publication No. 2011-151131.